Restricted volume self-cleaning oven



Nov. 26, 1968 I R. L. BRITT 3,413,443

RESTRICTED VOLUME SELF-CLEANING OVEN Filed July 28, 1966 2 Sheets-Sheet l INVENTOR RONALD L. BRITT A TT'Y Nov. 26, 1968 R. L. BRITT 3,413,443

RESTRICTED VOLUME SELF-CLEANING OVEN Filed July 28 1966 2 Sheets-Sheet 2 I/// III IN VE N TOR ATT'Y United States Patent 3,413,443 RESTRICTED VOLUME SELF-CLEANING OVEN Ronald L. Britt, Lombard, Ill., assignor to General Electric Company, a corporation of New York Filed July 28, 1966, Ser. No. 568,425 Claims. (Cl. 219393) cavity, by means of heaters, to a level substantially above 7 that of normal cooking temperatures. At the high temperatures reached, pyrolysis causes chemical decomposition of any food soil on the oven liner into gaseous products, that are then removed by suitable ventilating means. A basic patent in this art is that of Bohdan Hurko, No. 3,121,158, issued Feb. 11, 1964, and assigned to the General Electric Company, assignee of the present invention.

While the effectiveness of the pyrolysis technique to make ovens self-cleaning, and its acceptability to the consumer, are beyond question, the structure of the presently marketed type of device is one with inherently costly features. These result, in substantial part, from the fact that the entire volume within the oven is heated to the temperature where pyrolysis occurs. This requires application of power for a considerable length of time, plus a major effort insofar as insulating the oven from the outer surface of the range is concerned.

It is therefore an object of this invention to provide an oven construction which will allow the use of the pyrolysis phenomenon to effect cleaning of the walls of an oven while requiring little more than the usual amount of insulation.

More specifically, it is an object of my invention to achieve the above goal by causing the walls of the oven to be movable so as to form small volumes about the heating elements, thereby greatly reducing the volume which must be heated to the pyrolysis temperature.

A further and more specific object of my invention is to achieve the aforementioned small volumes by suitable hinging and dimensioning of the walls of the oven.

In one aspect thereof, my invention provides a cooking oven wherein the usual top, bottom, rear and side walls form a front access doorway, with a door for either closing the doorway or providing access to the inside of the oven. Electric heating elements are positioned in the oven, one beneath the top wall adjacent and parallel to it, and the other above the bottom wall, also in a plane adjacent and parallel to it.

The back Wall of the oven is covered by a back liner member which is hingedly mounted along one horizontal edge thereof, and the side walls are covered by a pair of side liner members which are also hingedly mounted along a horizontal edge. The horizontal edges of the back liner and of the side liners respectively are oppositely selected; in other words, where the top horizontal edge of the back liner is selected for hinging, the bottom horizontal edges of the side liners are selected.

The height of the side liners is about half the distance between them. As a result of this, the side liner members may be swung into cooperatively covering relation to one of the elements so as to enclose it in a relatively small volume. Similarly, the back liner may be swung into covering relation to the other of the elements, also enclosing it in a small volume. Whichever of the liner members cooperate with the top wall to provide the small volume is provided with releasable retaining means for retention in the pivoted position until release is desired.

With the small volumes enclosing the heating elements, and with the volumes being formed in effect by the walls and liners of the oven, food soils on the walls on the liner members covering the walls are degraded into gaseous products by the previously mentioned pyrolysis phenomenon when the elements are energized.

The subject matter which I regard as my invention is particularly pointed outand distinctly claimed in the concluding portion of this specification. My invention, however, both as to organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings.

In the drawings,

FIGURE 1 is a side cross-sectional view of a range having an oven incorporating the novel features of my invention;

FIGURE 2 is a view in perspective of the range of FIGURE 1, showing the oven in condition for use;

FIGURE 3 is a view similar to FIGURE 2 illustrating the oven in the process of preparation for a self-cleaning operation; and

FIGURE 4 is a front elevational partly schematic view of the oven liner members of the oven as shown in FIG- URE 3.

Referring now to FIGURE 1, there is shown a high oven range in which the oven of my invention has been incorporated. The general structure of the range in FIG- URE 1 conventionally includes a cooking surface 1 having a plurality of surface cooking units 2 on which cooking operations such as boiling and frying may be conducted. The vapors rising from the cooking operations being per formed on surface units 2 may be carried off with air which is circulated by means of an air circulation and filtering system generally indicated by the numeral 3. The specifics of the air circulating and filtering system form no part of the present invention, and the system shown is that illustrated and claimed in Patent 3,131,688, issued on May 5, 1964, to N. J. Lipstein, and assigned to the same assignee as the present invention.

The range of FIGURE 1 includes an oven 4 having a pair of side walls, one of which is shown at 5, a top wall 6, a bottom wall 7, and a back wall 8. The walls together define an access opening 9 to the oven which is conventionally closed by .a door 10. Door 10 may be opened, as illustrated in FIGURE 2, by any conventional hinging mechanism so as to provide access to the interior of the oven when so desired. Each of side walls 5 is covered by a side panel 11. Each side liner member 11 is substantially coextensive with a side 5, and is hingedly mounted by a suitable hinge, such as that shown by numeral 12, along its upper horizontal edge. Panel 11 may thus be pivoted about its upper horizontal edge in a manner best shown in FIGURES 3 and 4.

Top and bottom walls 6 and 7 have dished central areas 13 and 14 respectively, and a pair of electric heating elements 15 and 16 are mounted to the upper and lower walls so as to provide a serpentine configuration substantially restricted within the dished portions. Unit 15 is in a plane substantially parallel to and adjacent the upper wall 6; similarly, unit 16 is in a plane parallel to and substantially .adjacent the lower wall 7. It will be understood that each of the elements 15 and 16 may be connected to a suitable source of power, so that the units may be energized and provide heating within the oven.

In the same way that liners 11 cover sides 5, a back liner number 17 is substantially coexistensive with wall 8 so as to cover it. Back liner 17 is mounted by a hinge 1.8 at its lower horizontal edge to the oven wall so as to pivotable about that edge in a forward direction. The pivoting action of liner 17 may best be seen by reference to FIGURES 3 and 4.

It will be understood that the units and 16 are manually operated by controls such as that shownxat 19 in FIGURE 1, so that suitable cooking operations may be carried out within the oven 4. A suitable rack structure, generally indicated by the numeral 20, is removably provided within over 4 so as to support cooking vessels at the desired level during cooking operations. It will be understood that, in a manner known in the art, the rack structure 20 may be removed from the oven so that the inside of the oven is empty, substantially .as shown in FIGURES l and 3.

The oven structure shown is of the type which has a ventilation system permitting broiling operations to be carried out while door 10 is closed. In order to permit this, door 10 is formed so that in the closed position it provides an inlet 20a for air which may then pass through the oven, as shown by the arrows, to a space 21 at the top of the back wall 8, down through passageway 22 behind the back Wall, and from there in to the previously mentioned air circulation and filtering system 3.

The dimensioning of the diiferent components of the In the preferred form, the depth and height of the oven are to be substantially similar, while the width of the oven, that is, the distance between side liner members, is to be about twice as great. These approximate dimensions are, in fact, presently provided in the ovens of some ranges marketed by applicants assignee, which have an oven 26 inches wide, just over 12 inches high, about 14 /2 inches deep. Such dimensions, together with the other structure defined above, permit the highly advantageous result which will now be described more clearly herebelow;

During ordinary use of oven 4, the liners 11 and 17 are positioned as shown in FIGURES 1 and 2 so as to cover the side and back walls respectively. The liner which is hinged at the lower edge thereof, that is, liner 17, may be provided with a catch member 23 which snaps in a conventional manner into a receiving opening provided in the back wall 8 so as to be releasably retained in the position of FIGURE 1. Similarly, fastener projections 24 may be provided near the base of each side panel 11, with each projection 24 being received, when the panel is pivoted upwardly, so as to be caught in an opening 25 formed in the top wall 6. This permits the side liners 11 to be retained in their fully upwardly pivoted position, shown in dotted outline in FIGURE 4. Liners 11 are shown in full lines at an intermediate position during their swing up from their vertical position to their horizontal position. Similarly, in FIGURE 4, back panel 17 is shown at the same intermediate position as in FIGURE 3 in full lines, and is shown in dotted lines after it has been moved fully into a horizontal plane.

When it is desired to have the exposed surfaces of oven 4 cleaned, the rack structure 20 .is removed. This leaves the main soil-receiving surfaces, i.e., top and bottom walls 6 and 7, panels 5 covering the side walls, and panel 17 covering the back wall.

When panels 11 are pivoted up in a horizontal plane, the fact that the width of the oven is twice the height thereof causes them to meet, as shown in FIGURE 4. Also, in this position the retaining members 24 cooperate with openings 25 to hold the liners 11. In this horizontal position, liners 11 cooperate with the top wall 6 to enclose the heating element 15 in a very small volume. In a similar manner, the downward pivoting of liner 17 to its horizontal position causes it to cooperate with the bottom wall 14 to enclose heating element 16 in a very small volume. Thus, he internal exposed surfaces which normally receive food soil in an oven are hingedly movable into cooperative relationship with each other to provide small volume enclosures about each of the heating elements.

With such small volumes, it can readily be seen that by an appropriate control both heating elements may be energized, preferably with equal wattages, to provide heat energy to the small volumes enclosing them. As a result of the small volume, a very high temperature is quickly reached so that pyrolysis takes place on those surfaces which form the volume. The fact that there is such a small volume to be heated permits the time consumed for cleaning by pyrolysis to be decreased substantially from that which exists in self-cleaning ovens on the market today. There is the additional point that the major part of the space in the oven is outside the small confined volumes, and does not need to be raised to a high temperature. In fact, this major part of the space does not reach nearly as high a temperature during the time required for selfcleaning as is reached in the enclosed volumes. This results in a savings insofar as use of energy is concerned, and also permits a conventional oven structure to be used with little additional insulation and safety devices commonly in use at the present time in self-cleaning ovens.

Thus, the entire construction may be achieved more economically than those presently on the market, while the major part of the benefits, that is, the cleaning of the inner surfaces forming the oven cavity, is achieved without need for scrubbing or scouring.

The same ventilating system that operates to ventilate the oven during broiling operations also serves to carry oil the gaseous products of pyrolysis during cleaning operations. This is achieved simply by having the ventilating system operate as previously described. These gaseous products of pyrolysis escape from the restricted volumes since they are in no wise tightly closed, and are then carried off through the ventilating system, as previously briefly described.

It will be understood that, while in accordance with the patent statutes I have described what at present is considered to be the preferred embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from my invention. I therefore aim, in the appended claims, to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A cooking oven comprising:

(a) top, bottom and rear walls, a pair of side walls, and

a front access doorway; I (b) door means for closing said doorway;

(c) a first electric heating element positioned beneath the top wall in a plane adjacent and parallel thereto;

(d) a second electric heating element positioned above said bottom wall in a plane adjacent and parallel thereto;

(e) a back liner member substantially coextensive with said back Wall and hingedly mounted along one hori-- zontal edge thereof;

(f) a pair of side liner members substantially coextensive with said pair of side Walls respectively, each said side liner member being hingedly mounted along one horizontal edge thereof oppositely positioned in said oven in a vertical sense with respect to said one horizontal edge of said back liner member;

g) said side liner members having a height about half the ditsance between them, whereby said side liner members may be swung into cooperatively covering relation to one of said elements and said back liner member may be swung into covering relation to the other of said elements so that said elements are respectively substantially enclosed in small volumes formed primarily by said top and bottom walls and by said liner members; and I (h) means for releasably retaining each liner member which cooperates with said top wall in the position providing said small volume;

(i) whereby food soils on said top and bottom walls and said liner members are degraded intogaseous products by pyrolysis when said elements are energized and said small volumes are provided.

2. The structure defined in claim 1 wherein said side liner members are hinged along their top edges and said back liner member is hinged along its bottom edge.

3. The structure defined in claim 1 wherein said door provides air inlet means when in its closed position, outlet means are formed at the back of said oven, and air circulation means are provided for drawing air in through said door, through said oven, and out through said back outlet.

References Cited UNITED STATES PATENTS 3,121,158 2/1964 Hurko 219-397 3,131,688 5/1964 Lipstein l2621 X 3,302,000 1/1967 Sherman 219393 BERNARD A. GILHEANY, Primary Examiner.

V. Y. MAYEWSKY, Assistant Examiner. 

1. A COOKING OVEN COMPRISING: (A) TOP, BOTTOM AND REAR WALLS, A PAIR OF SIDE WALLS, AND A FRONT ACCESS DOORWAY; (B) DOOR MEANS FOR CLOSING SAID DOORWAY; (C) A FIRST ELECTRIC HEATING ELEMENT POSITIONED BENEATH THE TOP WALL IN A PLANE ADJACENT AND PARALLEL THERETO; (D) A SECOND ELECTRIC HEATING ELEMENT POSITIONED ABOVE SAID BOTTOM WALL IN A PLANE ADJACENT AND PARALLEL THERETO; (E) A BACK LINER MEMBER SUBSTANTIALLY COEXTENSIVE WITH SAID BACK WALL AND HINGEDLY MOUNTED ALONG ONE HORIZONTAL EDGE THEREOF; (F) A PAIR OF SIDE LINER MEMBERS SUBSTANTIALLY COEXTENSIVE WITH SAID PAIR OF SIDE WALLS RESPECTIVELY, EACH SAID SIDE LINER MEMBER BEING HINGEDLY MOUNTED ALONG ONE HORIZONTAL EDGE THEREOF OPPOSITELY POSITIONED IN SAID OVEN IN A VERTICAL SENSE WITH RESPECT TO SAID ONE HORIZONTAL EDGE OF SAID BACK LINER MEMBER; (G) SAID SIDE LINER MEMBERS HAVING A HEIGHT ABOUT HALF THE DISTANCE BETWEEN THEM, WHEREBY SAID SIDE LINER MEMBERS MAY BE SWUNG INTO COOPERATIVELY COVERING RELATION TO ONE OF SAID ELEMENTS AND SAID BACK LINER MEMBER MAY BE SWUNG INTO COVERING RELATION TO THE OTHER OF SAID ELEMENTS SO THAT SAID ELEMENTS ARE RESPECTIVELY SUBSTANTIALLY ENCLUSED IN SMALL VOLUMES FORMED PRIMARILY BY SAID TOP AND BOTTOM WALLS AND BY SAID LINER MEMBERS; AND 